space station, an artificial structure placed in orbit and having the pressurized enclosure, power, supplies, and environmental systems necessary to support human habitation for extended periods. Depending on its configuration, a space station can serve as a base for a variety of activities. These include observations of the Sun and other astronomical objects, study of Earth’s resources and environment, military reconnaissance, and long-term investigations of the behaviour of materials and biological systems—including human physiology and biochemistry—in a state of weightlessness, or microgravity.

Small space stations are launched fully assembled, but larger stations are sent up in modules and ... (100 of 4,801 words)